Cyclic cytidine 2',3'-phosphate: molecular structure

Monoclinic crystals of the sodium salt of cytidine 2',3'-phosphate contain two anions in the asymmetric unit. Both bases are in the syn conformation, and the nucleotides are stacked together into an antiparallel stranded ribbon with the bases 3.3 angstroms apart. One ribose ring is planar, and the other has oxygen-1' puckered toward carbon-5'. The phosphorus atoms in the five-membered ester rings are puckered toward the sugars. The conformations about the carbon-4'-carbon-5' bonds are gauche-trans and gauche-gauche.     

对甜菜夜蛾高毒力Bt新菌株的PCR-RFLP分析及生物活性测定

利用PCR-RFLP对Bt.新菌株cyz-13,T4-3的基因型进行分析。结果表明,cyz-13含有cry1Aa,cry1Ac,cry1Bc,cry2Ab4种基因型,其中cyz-13菌株的PCR产物的酶切片断类型不同于已知的基因类型;T4-3菌株含有cry1Aa,cry1Ac,cry1Ag,cry2Ac,cry1Ia5种基因型。室内生测结果显示,两菌株对甜菜夜蛾、粘虫、棉铃虫、玉米螟均具有高毒力,好于H D-1标准菌株。两菌株的发酵液均有杀虫活性,二者上清的杀虫因子不同。     

Adenosine 3',5'-monophosphate modulates thyrotropin receptor clustering and thyrotropin activity in culture

A biologically active rhodamine conjugate of thyrotropin binds at 4 degrees C to diffusely distributed membrane thyrotropin receptors which patch and become endocytosed into thyroid cells in a temperature-sensitive process. When the cells are first incubated with 8-bromo-cyclic adenosine monophosphate at 37 degrees C, the conjugate also binds to clustered receptors at 4 degrees C. Furthermore, 8-bromo-cyclic adenosine monophosphate reduces the amount of adenosine 3',5'-monophosphate (cyclic AMP) induced by thyrotropin. Hence, increased intracellular cyclic AMP induces receptor patching and reduces the concentration of cyclic AMP normally induced by thyrotropin. This suggests that cyclic AMP acts both as the second messenger of thyrotropin and also as the regulator of the level of thyrotropin receptors.     

Studying the antagonistic activity of Lactobakterin against Rhodococcus equi in vivo

The high antagonistic activity of the probiotic Lactobakterin against Rhodococcus equi in in vitro experiments was the base for studying this probiotic in vivo. In the course of the researches, the intravenous injection of Lactobakterin into white mice was approved and the advisability of this method in the conditions of the experiment was shown. The antagonistic activity of the probiotic Lactobakterin was studied on the mouse model against the virulent strain of Rhodococcus equi. It was stated that the antagonistic activity of the probiotic is 1.25-fold higher under the three-fold intravenous injection into the mice infected intraperitoneally with the strain of Rhodococcus equi than under the 2-fold injection. The intravenous injection of the probiotics is possible upon the condition of their short-term application during the critical periods for the animal.     

Fluorescent modification of adenosine 3',5'-monophosphate: spectroscopic properties and activity in enzyme systems

The synthesis of a highly fluorescent analog of adenosine 3',5'-monophosphate, namely, 1,N(6)-ethenoadenosine 3',5'-monophosphate, has provided a powerful probe for systems involving adenosine 3',5'-monophosphate. The potential utility of this analog is indicated by its long fluorescent lifetime, detectability at low concentration, and relatively long wavelength of excitation (300 nanometers). In protein kinase systems it is a highly acceptable substitute for adenosine 3',5'-monophosphate.     

苯基吡唑类化合物的合成、杀虫活性及对蜜蜂的毒性

【目的】以氟虫腈结构为骨架,寻找具有杀虫活性和对环境友好型的苯基吡唑类化合物。【方法】以不同取代基的苯胺为原料,经2步法合成含有不同取代基的苯基吡唑类化合物1～21;产物结构经1H NMR、13C NMR和ESI-MS分析确定;采用浸液法测定目标产物对小菜蛾Plutella xylostella的生物活性;测定化合物1、5、12和16对中华蜂Apis cerana的急性经口毒性。【结果】化合物1、5、12和16处理小菜蛾24 h的LC50分别为0.26、0.95、0.33和1.10 mg·L~(-1),其中化合物1和12对小菜蛾的活性优于氟虫腈。化合物5、12和16对中华蜂的急性经口毒性比氟虫腈(0.05mg·L~(-1))低,但仍属于剧毒,LC50分别为0.21、0.22和0.09 mg·L~(-1)。构效关系表明,苯环的取代基对苯基吡唑类化合物的活性影响很大,当苯环邻位存在—Cl或—Br、对位为—Cl、—CF3或—OCF3时,化合物对小菜蛾表现出极好的活性。【结论】氟虫腈苯环取代基的替换可以提高对小菜蛾的生物活性、降低对中华蜂的毒性,研究结果对今后芳基吡唑类杀虫剂开发、结构优化具有一定的指导意义。     

猪EIF2S3基因克隆测序及其组织表达谱分析

[目的]克隆猪EIF2S3基因mRNA全长,并进行生物信息学分析及检测其在猪各组织中的表达特征,为研究真核翻译起始因子2(eIF2)蛋白γ亚基的生物学功能打下基础.[方法]以荣昌猪胸腺mRNA为模板,采用RCAE-PCR克隆EIF2S3基因的mRNA全长序列,在线完成各种生物信息学分析后,利用实时荧光定量PCR分析猪EIF2S3基因的组织表达特征.[结果]猪EIF2S3基因mRNA全长1813 bp,其中蛋白质编码区(CDS)长1419 bp,5'UTR区、3'UTR区分别长14和380 bp,编码472个氨基酸.EIF2S3蛋白分子量51.1 kD,理论等电点(pI)8.62,包含58个带正电的氨基酸和52个带负电的氨基酸,其前体蛋白靠近N端区域有一个强疏水区;EIF2S3蛋白的空间结构由α-螺旋、β-折叠、延伸及无规则卷曲构成.EIF2S3蛋白氨基酸序列与狗和大白鼠的相似性最高(99.6%),其次是马、猫、牛、羊和人类(99.4%),与斑马鱼的相似性最低(96.6%).EIF2S3基因在猪的心脏、胸腺和淋巴组织中表达量较高,在脾脏和肌肉中呈中度表达,在肾脏中的表达量较低,而在肝脏中基本不表达.[结论]猪EIF2S3基因全长1813 bp,在核酸和氨基酸水平上与其他物种的EIF2S3基因高度同源,尤其与狗和大白鼠的遗传距离最近;其在猪心脏、胸腺和淋巴组织中的表达量较高,在肝脏中基本不表达,据此推测EIF2S3参与合成的蛋白更多地参与心脏泵血和免疫相关功能,基本不发挥能量代谢功能.     

Effect of adenosine 3',5'-monophosphate on neuronal pacemaker activity: a voltage clamp analysis

Bursting pacemaker activity in nerve cells can be modified for long periods by synaptic input of short duration. There is evidence that cyclic nucleotides may play a role in these modifications. The predominant effect of elevated levels of adenosine 3',5'-monophosphate in Aplysia neurons was an increased slope conductance to hyperpolarizing pulses, evident in voltage clamp records. A similar increase in slope conductance was seen as one component of maximum strength synaptic stimulation, which is consistent with the idea that cyclic nucleotides are important in the expression of synaptic alteration of bursting pacemaker activity.     

7，3＇，5＇-三取代黄烷酮和黄酮醇类化合物的合成

以3,5-二羟基苯甲酸和间苯二酚为原料,分别经酯化、乙酰化、甲氧甲氧基保护或甲基化、酰肼化、氧化、醛酮缩合、环化、Algar-Flynn-Oyamada反应以及脱保护基等步骤,以21%~32%的总收率合成了7,3’,5’-三取代黄烷酮1a~1b和黄酮醇类化合物2a~2b,所有合成产物通过1H NMR,IR,MS进行了结构确证.其中黄烷酮1b是从药用植物中间锦鸡儿Caragana intermedia Kang etH.C.Fu中分离得到的新天然有机化合物,此次为首次全合成.     

In vivo administration of anti-CD3 prevents malignant progressor tumor growth

Malignant progressor tumors are only weakly immunogenic and can evade host recognition and rejection. One approach to therapy involves activation of the host antitumor cellular effector mechanisms. Since monoclonal antibodies to CD3 (anti-CD3) can activate T cells in vitro, an attempt was made to determine if tumor immunity could be achieved by the administration of anti-CD3 in vivo. T lymphocytes from mice injected with anti-CD3 showed increased interleukin-2 receptor (IL-2R) expression, increased proliferation to recombinant IL-2 (rIL-2), and enhanced reactivity in both an allogeneic mixed lymphocyte reaction and a mixed lymphocyte tumor culture. Malignant tumor growth in treated mice was also examined. The anti-CD3 treatment prevented tumor outgrowth that would have killed untreated animals and also stimulated an in vivo response against a malignant progressor tumor providing lasting tumor immunity.     

In vitro and in vivo consequences of VLA-2 expression on rhabdomyosarcoma cells

Cloned integrin alpha 2 subunit complementary DNA was expressed on human rhabdomyosarcoma (RD) cells to give a functional VLA-2 (alpha 2 beta 1) adhesion receptor. The VLA-2-positive RDA2 cells not only showed increased adhesion to collagen and laminin in vitro, but also formed substantially more metastatic tumor colonies in nude mice after either intravenous or subcutaneous injection. These results show that a specific adhesion receptor (VLA-2) can markedly enhance both experimental and spontaneous metastasis. In contrast to the metastasis results, there was no difference in either the in vitro growth rate or apparent in vivo tumorigenicity of RD and RDA2 cells.     

抗弧菌杀鱼假交替单胞菌2515的潜在毒性及热处理脱毒后抗菌效果

为评估一株具有弧菌拮抗功能的杀鱼假交替单胞菌2515 Pseudoalteromonas piscicida 2515 (以下简称"菌株2515" ) 对海水养殖动物的毒性, 并确定一种有效的热处理脱毒方法, 在中国明对虾Fenneropenaeus chinensis育苗水体中分别添加浓度为105、 106、 107...     

抗弧菌杀鱼假交替单胞菌2515的潜在毒性及热处理脱毒后抗菌效果

为评估一株具有弧菌拮抗功能的杀鱼假交替单胞菌2515 Pseudoalteromonas piscicida 2515(以下简称菌株2515)对海水养殖动物的毒性,并确定一种有效的热处理脱毒方法,在中国明对虾Fenneropenaeus chinensis育苗水体中分别添加浓度为10⁵、105、10⁶、106、10⁷、107、10⁸ CFU/mL的菌株2515,测试其对中国明对虾受精卵孵化及幼体发育的影响。结果表明:水体中添加浓度高于108 CFU/mL的菌株2515,测试其对中国明对虾受精卵孵化及幼体发育的影响。结果表明:水体中添加浓度高于10⁵ CFU/mL的菌株2515后,显著降低了无节幼体变态发育至蚤状幼体的成活率(P<0.05);分别应用血平板及显微观察法测试菌株2515对羊、鱼及对虾血细胞的溶血活性,结果显示,该菌对羊及鱼红细胞均具溶血活性,而对凡纳滨对虾Litopenaeus vannamei血细胞无溶血活性;设置不同温度(40、45、50、55、60、65、75℃)热处理菌株2515及其破碎液,结果显示,55℃1 h能够灭活该菌,且失去对鱼类红细胞的溶血活性,而抑菌物质活性可提高55.8%。研究表明,菌株2515对鱼虾具有潜在毒性,选择适当热处理,既能灭活溶血活性还可提高抗菌活性。     

Practical synthesis of prostratin, DPP, and their analogs, adjuvant leads against latent HIV

Although antiretroviral therapies have been effective in decreasing active viral loads in AIDS patients, the persistence of latent viral reservoirs prevents eradication of the virus. Prostratin and DPP (12-deoxyphorbol-13-phenylacetate) activate the latent virus and thus represent promising adjuvants for antiviral therapy. Their limited supply and the challenges of accessing related structures have, however, impeded therapeutic development and the search for clinically superior analogs. Here we report a practical synthesis of prostratin and DPP starting from phorbol or crotophorbolone, agents readily available from renewable sources, including a biodiesel candidate. This synthesis reliably supplies gram quantities of the therapeutically promising natural products, hitherto available only in low and variable amounts from natural sources, and opens access to a variety of new analogs.     

In vivo modulation of cytolytic activity and Thy-1 expression in TCR-gamma delta+ intraepithelial lymphocytes

Although the functional aspects of the alpha beta T cell antigen receptor (TCR) found on most peripheral T cells are well described, the function of the gamma delta TCR remains unclear. Murine intraepithelial lymphocytes (IEL) of the small intestine are CD8+, express the gamma delta TCR, and are constitutively lytic. Fresh IEL from germ-free mice had no lytic activity. Moreover, whereas IEL from normal mice are 30 to 50 percent Thy-1+, IEL from germ-free did not express Thy-1. Acclimation of germ-free mice to nonsterile conditions resulted in the generation of Thy-1+ IEL and induction of lytic activity. Thus CD8+ TCR-gamma delta IEL were regulated by externally derived stimuli via a specific functional interaction between IEL and gut-associated antigens.     

Crystal and molecular structure of adenosine 3',5'-cyclic phosphate

The structure of adenosine 3',5'-cyclic phosphate has been determined by single-crystal x-ray diffraction. The two molecules in the asymmetric unit show different conformation about the glycosidic bond, while other structural details are essentially the same. The furanose rings are puckered with the C(4') atom out of the best four-atom plane. The bond lengths and angles appear to be normal.     

Adenosine 3',5'-monophosphate, adrenocorticotropic hormone, and adrenocortical cytosol protein synthesis

In cultures of mouse adrenocortical tumor cells (Sato's minimal deviation Y-1 clonal strain), the acceleration of steroid biosynthesis after exposure to adrenocorticotropic hormone or cyclic adenosine 3',5'-monophosphate is maximum within 15 to 60 minutes and precedes any significant increase in labeling of protein with [4,5-(3)H]leucine. However, when cytosol proteins are separated by acrylamidegel electrophoresis, rapid changes in the amount and labeling of several protein fractions are evident in less than 30 minutes and are no longer evident within 60 minutes. This finding supports the proposal that the effects of tropic hormones and their intracellular mediators involve rapid selective effects on protein synthesis.     

Removal of Stratospheric O3 by Radicals: In Situ Measurements of OH, HO2, NO, NO2, ClO, and BrO

Simultaneous in situ measurements of the concentrations of OH, HO(2), ClO, BrO, NO, and NO(2) demonstrate the predominance of odd-hydrogen and halogen free-radical catalysis in determining the rate of removal of ozone in the lower stratosphere during May 1993. A single catalytic cycle, in which the rate-limiting step is the reaction of HO(2) with ozone, accounted for nearly one-half of the total O(3) removal in this region of the atmosphere. Halogen-radical chemistry was responsible for approximately one-third of the photochemical removal of O(3); reactions involving BrO account for one-half of this loss. Catalytic destruction by NO(2), which for two decades was considered to be the predominant loss process, accounted for less than 20 percent of the O(3) removal. The measurements demonstrate quantitatively the coupling that exists between the radical families. The concentrations of HO(2) and ClO are inversely correlated with those of NO and NO(2). The direct determination of the relative importance of the catalytic loss processes, combined with a demonstration of the reactions linking the hydrogen, halogen, and nitrogen radical concentrations, shows that in the air sampled the rate of O(3) removal was inversely correlated with total NOx, loading.     

1株烟草赤星病拮抗芽孢杆菌的鉴定与活性研究

【目的】筛选对烟草赤星病具有拮抗作用的芽孢杆菌并进行鉴定,同时研究其抗菌作用。【方法】从陕西、云南、湖北和河南4省烟区采集烟草根际土壤和烟叶,从中分离筛选烟草赤星病拮抗芽孢杆菌,并对拮抗性最强的1株芽孢杆菌进行形态学、生理生化特性、16S rDNA序列鉴定及粗提物抑菌作用测定。【结果】从烟草表面及根际土壤分离得到的芽孢杆菌中有10株对烟草赤星病有拮抗效果,将其中效果最好的1株芽孢杆菌定名为M-07C2F,其抑菌条带宽度达14.2 mm;通过16S rDNA测序并结合其形态和生理生化特征,鉴定该菌株为解淀粉芽孢杆菌。通过显微观察发现,M-07C2F菌株使烟草赤星病病原真菌的菌丝生长出现畸形,菌丝体内部细胞原生质体分布不均匀,部分菌丝内原生质有流出形成空壳的现象。在离体条件下采用生长速率法,测得其对烟草赤星病菌丝生长有抑制作用,EC₅₀为12.82 mg/L;在活体条件下采用田间小区试验,测得当M-07C2F菌株粗提物质量浓度为80 mg/L时,其对烟草赤星病的防治效果达到86.0%。【结论】菌株M-07C2F对烟草赤星病菌的抑菌作用明显,该菌株通过抑制烟草赤星病菌菌丝生长、减少孢子萌发来抑制病菌对植株的侵染,且菌株粗提物质量浓度越高,抑菌能力越强。